The present invention relates to generating gaseous fuel from a solid fuel, such as coal, that can be burned in a gas turbine based power plant.
The high efficiency, low capital cost and short lead time of gas turbine based power plants make them particularly attractive to electric utilities as a means of producing electrical power. Unfortunately, traditionally, gas turbines have been limited to operation on expensive, sometimes scarce, fuels - chiefly, distillate oil and natural gas. As a result of the ready availability and low cost of coal, considerable effort has been expended toward developing a gas turbine system for generating electrical power that can utilize coal as its primary fuel.
In one approach, compressed air from the gas turbine compressor is used to partially combust coal in a gasifier to produce a hot, low to medium heating value fuel gas. This hot fuel gas is combusted and then expanded in the turbine section of the gas turbine, which produces useful shaft power. Unfortunately, such systems can result in unacceptable emissions, especially in terms of particulate, sulfur and alkali emissions, unless prohibitively expensive clean-up measures are employed. In addition, the heating value of the fuel produced by the gasifier is lower than desired.
It is therefore desirable to provide a system and method for effectively producing a clean gaseous fuel, which can be burned in a gas turbine combustor, from a solid fuel, such as coal.